1. Field of the Invention
The present invention relates to a vehicle power-supply unit configured to prevent a rush current in a vehicle power-supply system since power activation till start-up.
2. Description of the Background Art
With the aim of improving fuel efficiency for a reduction of environmental burdens, there is a vehicle power-supply system requiring at least two independent power supplies to increase power generation efficiency of a generator and to use regenerative energy during deceleration. This vehicle power-supply system requires a voltage transducer to handle power supplies having different voltages and has a problem of how to prevent a rush current at start-up and protect elements from a backflow and during reverse connection.
PTL 1 discloses a system adopting a step-up DC-to-DC converter, in which protection against reverse connection is provided, and also a rush current is prevented and elements are protected by performing normal charge control by way of constant voltage control.